These inventions relate to three-dimensional (3-D) display systems and methods, and, in particular, to a 3-D display system and method in which 3-D viewing is permitted at multiple viewing positions, such as multiple viewing angles or distances, from the screen.
Creating the illusion of three-dimensional (3-D) images on a 2-D display device or projection screen has been attempted for many years. In the 1950""s, 3-D movies were popular with polarized glasses worn to separate images for the left and right eye to provide for a stereoscopic view of the movie. Another area in which 3-D imagery has been attempted is on raster scan displays. Generally, when the term 3-D is used in regard to computer graphics, the term is referring to planar generated 3-D images that are created using geometric perspective and projection transformations and other monocular depth cues such as hidden line removal, surface modeling, shading, texture mapping, and rotation. These techniques are appropriate for computer games and CAD application software but not for viewing camera-generated images such as used by the television industry.
Stereoscopic images present the viewer with slightly different perspectives for the left and right eyes which fuse together to provide a sense of depth, in a process called stereopsis. Stereoscopic displays typically require the use of some device worn by the viewer to separate the left and right eye perspectives. Autostereoscopic displays make use of some device externally attached to the 3-D display to generate the left and right views without the aid of a special viewing aid worn by the viewer. These devices are lenticular screens, light valves, floating displays, or other types of devices.
Autostereoscopic 3-D methods are preferred because of elimination of the need for special glasses to separate the left and right eye images. The lenticular screen has been investigated extensively for use in autostereoscopic displays. The lenticular screen uses vertically oriented stereoscopic image pairs and focuses them at the proper point for viewing. Using a fixed image under the lenticular screen will only allow one viewer to be in focus with the 3-D image.
Prior art patents have presented different methods for generation of 3-D displays. Several prior art displays use the concept of generating vertical stereoscopic image strips projected onto the back of a lenticular screen. See, e.g., U.S. Pat. Nos. 4,541,007; 4,214,257; 5,430,474; 5,614,941; 4,872,750.
It is known that by multiplexing two camera signals and generating stereoscopic images projected to a lenticular screen that a 3-D image is able to be viewed. See e.g., U.S. Pat. No. 4,214,257. However, U.S. Pat. No. 4,214,257 does not provide for more than a single user.
It is also known that if five camera signals are multiplexed and properly placed in horizontal succession behind a lenticular screen, multiple viewing locations are obtained. See e.g., U.S. Pat. No. 4,541,007.
It is also known that 3-D displays are created by floating one image above another using devices such as the LCD. See e.g., U.S. Pat. Nos. 5,430,474 and 5,614,941. U.S. Pat. Nos. 5,430,474 and 5,614,941 disclose different concepts for generation of 3-D displays as they do not generate vertical image strips for presentation to the lenticular screen.
It is further known that the time multiplexing of camera images are used to present 3-D autostereoscopic images to multiple viewers by use of a LCD shutter device. See e.g., Moore, J. R., Dodgson, N. A., Travis, A. R. L., and Lang, S. R. xe2x80x9cTime-Multiplexed Color Autostereoscopic Display.xe2x80x9d Proc. SPIE, Vol. 2653, pp. 10-19, 1996. This research performed at the University of Cambridge discloses the use of a LCD shutter device which is a different method for providing multiple viewing locations.
It is also known that 3-D images projected onto a lenticular screen follow a single user with a sensor attached to the user. The system uses mirrors to horizontally shift and change the size of the image to provide for horizontal and distance changes appropriate for the viewer to maintain sight of the 3-D image. See e.g., Tetsutani, N., Kishino, F. xe2x80x9c3-Dimensional Display Method without Special Glasses for Virtual Space Teleconferencing Systemxe2x80x9d Proc. SPIE, Vol. 1988, pp. 18-25, 1993. However, this projection system does not allow the flexibility and accuracy of a software-based system.
Each of the patents and articles discussed above is incorporated herein by reference.
Furthermore, FIGS. 1 to 4 illustrate the workings of a conventional prior art autostereoscopic 3-D system using two cameras A (2) and B (4) and employing a lenticular screen 12. FIG. 1 demonstrates the basic principle of a conventional prior art two camera 3-D autostereoscopic display system 1 incorporating a lenticular screen 12. Cameras A (2) and B (4) generate analog video signals that represent the left and right eye perspective views of the image object 6. These video signals are of any type (NTSC, PAL, SECAM, etc.) that are displayable on raster scan display devices 10. The respective analog video signals 3 and 5 from the cameras A (2) and B (4) are input to the graphics controller 8. The graphics controller 8 digitizes the analog signal so that processing of the signals 3 and 5 is accomplished with a digital signal processor or application specific graphics processor. The graphics processor multiplexes the left and right eye perspective views to create a stereoscopic image for the display with the proper timing. Once the stereoscopic raster image has been created digitally, it is then properly conditioned to form a signal 14 meeting the input requirements of the specific type of display device 10 being used. The lenticular screen 12 focuses the raster scan stereoscopic images to the proper locations for the viewer 16.
FIG. 2 shows conventional prior art views of left and right image strips showing two different perspectives derived from the two cameras A (2) and B (4) of the same image. These views demonstrate how the stereoscopic images appear on the display device 10 as seen in FIG. 1. The left view 20 and right view 18 are shown separately for illustration purposes only. The left view 20 shows the vertical strips of the stereoscopic image, which is generated from camera A (2), and the right view 18 shows the vertical strips of the image from camera B (4). These images represent the position of the image as displayed for one viewing location. For other viewing locations, the same vertical strips are shifted horizontally by small amounts.
To be able to view the stereoscopic image pairs, they must be aligned properly with the lenticular screen 12. The lenticular screen 12 has many individual lenses called lenticules 19. The lenticules 19 are vertically oriented convex lenses attached parallel to each other. For example, the display on display device 10 appears on the lenticular screen 12 as shown in FIG. 3. FIG. 3 shows a view of a stereoscopic image pair that appears on the back of one lenticule 19 in the lenticular screen 12. Each of the lenticules 19 has one vertical strip 32 of the stereoscopic image for the left eye 26 and one strip 34 for the right eye 24. The adjacent lenticules 19 have a strip of the camera views corresponding to the image shifted to the left or right. The position of the image strips 32 and 34 represent one viewing location.
To focus each of the stereoscopic image pairs 32 and 34 to the proper eye 26 and 24, they must be placed in unique locations at the back of the lenticules 19. Referring to FIG. 4, the vertical images are placed at the back of the lenticules 19 to maintain the proper stereoscopic relationship. The left view strips 32 and right view strips 34 placed at the back of the lenticules 19 respectively provide left eye 26 and right eye 24 stereoscopic views which are in focus for the lenticules 19. With all image strips placed in the proper locations at the back of the lenticules 19, the viewer is able to observe a complete stereoscopic 3-D image on the lenticular screen 12.
The problem with the basic operation of the above conventional prior art stereoscopic display system is that it is generally only able to be properly viewed by one viewer at a time at one position. The single viewer system will only have one position directly in front of the lenticular screen 12 in which the stereoscopic images will have the proper focus to the right and left eyes 24 and 26. Therefore, other viewers would, therefore, not be able to see or view the 3-D images on the screen 12.
While the above inventions provide 3-D viewing using fixed lens or screen techniques, none of these approaches permit 3-D viewing without the use of special glasses or aids at multiple viewing positions, such as variable angular positions in front of the screen or at variable distances from the screen. All of the above-described approaches use a fixed display pattern behind a viewing lens to achieve the 3-D effect. None of these approaches take full advantage of modern video signal processing technology to present variable picture structures behind or at the back of a lenticular screen to achieve 3-D viewing from multiple, variable positions in front of the screen. Furthermore, none of the approaches described in the above references permit dynamic changing of the video presentation by a user with remote control to alter the viewing angle and distance to suit the comfort of the viewer. None of the above-described approaches oscillate a single image behind a lenticular screen to achieve multiple viewing locations.
The proposed invention generates 3-D autostereoscopic images on a raster scan display device. The system uses two cameras placed in stereoscopic relation to the object being viewed. The analog video signals from the two cameras are input to a graphics controller where they are digitized. These digital signals are processed to generate output video signals that are vertical image strips for the left and right eyes. These video signals are input to the display device. The display device is covered with a lenticular screen, that has a number of vertical lenticules wherein the stereoscopic image pairs are generated by the graphics processor for each vertical lenticule. The lenticule is a convex semi-cylindrical lens that focuses the stereoscopic image pairs to the left and right eyes.
In addition to producing the vertical image strips, the graphics controller oscillates the image strips horizontally by small amounts. This oscillation of the image strips causes a horizontal shift in the focal point of the image (i.e. new viewing position in a horizontal direction). The graphics processor produces multiple viewing locations by the rapid horizontal oscillation of the image strips to different locations.
The graphics processor also changes the width of the stereoscopic image strips being generated for the display device. This change in width alters the distance from the display at which the 3-D image is viewed. Variable width and horizontal oscillation of the image strips provides for the possibility of 3-D images being viewed from multiple, variable angular positions at different distances from the screen.
The proposed 3-D system also has the capability for individual viewer input to control the specific viewing location. Adjustable viewing locations are accomplished with the use of a remote control device. This remote control device allows an individual viewer to move from one location to another and adjust the 3-D image to be in focus at the new location. The inputs from the remote control are viewer number, change of horizontal location, and change of distance. The changing of location inputs is accomplished either with buttons (one set for horizontal shift and one set for distance shift), a joystick type input device, or the like.
It is therefore a principal object of this invention to provide a new and improved three dimensional (3-D) viewing system and method.
It is another object of this invention to provide a three dimensional (3-D) viewing system and method that provides multiple viewing positions for one or more viewers.
It is a further object to provide a 3-D viewing system and method using lenticular lens technology to provide 3-D images by focusing video images produced from multiple cameras and processed with high speed video processor technology to generate interleaved video images behind the lenticular screen.
It is a further object of this invention to provide multiple, adjustable viewing angles in front of the screen.
It is yet another object of this invention to provide 3-D image viewing at multiple, adjustable distances from the screen.
It is still another object of this invention to enable viewers to adjust the viewing position in front of the screen via a remote control device.
It is yet another object to achieve variable and multiple angular and distance viewing locations in front of the viewing screen by oscillating interleaved image strips and varying the width of these strips behind a lenticular viewing screen.
Further objects of the invention are apparent from reviewing the summary of the invention, detailed descriptions, and claims set forth below.
The above objects and advantages of the invention are achieved by a system for generating and displaying three-dimensional images of a scene on a screen that provides multiple viewing positions for one or more viewers. A stereoscopic video capture system picks up video images of the scene. A video signal processing unit processes the video images into video signals. The video signal processing unit has a graphics controller for controlling and processing the video signals into stereoscopic display signals. A display unit displays the stereoscopic display signals as stereoscopic display images on the screen, and the graphics controller manipulates the stereoscopic display images to provide multiple viewing positions of the stereoscopic display signals on the display unit of the screen to the one or more viewers. Multiple viewing angles and distances are provided for the one or more viewers. The stereoscopic display images are oscillated to provide multiple viewing angles. The stereoscopic display images comprise vertical image pair strips and dark vertical strips interposed between the vertical image pair strips. These strips are alternately interchanged in position for oscillating the stereoscopic display images, typically above a critical fusion frequency for human vision, to provide multiple viewing angles. The vertical image pair strips are varied in width to provide multiple viewing distances. A control unit, such as a remote unit or attached unit, is used for adjusting and updating the multiple viewing positions, such as multiple viewing angles or distances, of the stereoscopic display images on the screen for the one or more viewers.
The stereoscopic video capture system includes a first video camera arranged to capture the video images of the scene corresponding to a left stereoscopic image view of the scene and a second video camera arranged to capture the video images of the scene corresponding to a right stereoscopic image view of the scene. The video signal processing unit has an analog-to-digital converter for converting the video images from the stereoscopic video capture system to a digital signal and a graphics digital signal processor for processing the digital signal from the analog-to-digital converter to generate the stereoscopic image signals. The graphics digital signal processor processes the digital signal from the analog-to-digital converter and generates the stereoscopic display signals that are displayed on the screen as the stereoscopic display images. The stereoscopic display signals generated by the graphics digital signal processor comprises alternating, interleaved vertical strips of the video images of the scene to produce the three-dimensional images to the one or more viewers located at a particular viewing position in front of the screen. Positions of the vertical strips produced by the graphics digital signal processor are adjusted by the one or more viewers to optimize viewing effect of the three-dimensional images at different angular positions in front of the screen. The display unit further includes a display medium for displaying the video signals and a lenticular screen superimposed between the display medium and the one or more viewers to focus the stereoscopic display images on the screen.
The above objects and advantages of the invention are further achieved by a method of making a system for generating and displaying three-dimensional images of a scene on a screen providing multiple viewing positions for one or more viewers. A stereoscopic video capture system is provided for picking up video images of the scene. A video signal processing unit is provided for processing the video images into video signals wherein the video signal processing unit has a graphics controller for controlling and processing the video signals into stereoscopic display signals. A display unit is provided for displaying the stereoscopic display signals as stereoscopic display images on the screen, and the graphics controller is used to manipulate the stereoscopic display images to provide multiple viewing positions of the stereoscopic display signals on the display unit of the screen to the one or more viewers.
The above objects and advantages of the invention are also achieved by a method of generating and displaying three-dimensional images of a scene on a screen providing multiple viewing positions for one or more viewers. Video images of the scene are picked up by use of a stereoscopic video capture system. The video images are processed into video signals by use of a video signal processing unit. The video signals are controlled and processed into stereoscopic display signals by use of a graphics controller. The stereoscopic display signals are displayed as stereoscopic display images on the screen, and the stereoscopic display images are manipulated by use of the graphics controller to provide multiple viewing positions of the stereoscopic display signals on the screen to the one or more viewers. The stereoscopic display images are manipulated to provide multiple viewing angles or multiple viewing distances for the one or more viewers.
The preferred embodiments of the inventions are described below in the Figures and Detailed Description. Unless specifically noted, it is intended that the words and phrases in the specification and claims be given the ordinary and accustomed meaning to those of ordinary skill in the applicable art or arts. If any other meaning is intended, the specification will specifically state that a special meaning is being applied to a word or phrase. Likewise, the use of the words xe2x80x9cfunctionxe2x80x9d or xe2x80x9cmeansxe2x80x9d in the Detailed Description is not intended to indicate a desire to invoke the special provisions of 35 U.S.C. Section 112, paragraph 6 to define the invention. To the contrary, if the provisions of 35 U.S.C. Section 112, paragraph 6, are sought to be invoked to define the inventions, the claims will specifically state the phrases xe2x80x9cmeans forxe2x80x9d or xe2x80x9cstep forxe2x80x9d and a function, without also reciting in such phrases any structure, material, or act in support of the function. Even when the claims recite a xe2x80x9cmeans forxe2x80x9d or xe2x80x9cstep forxe2x80x9d performing a function, if they also recite any structure, material or acts in support of that means of step, then the intention is not to invoke the provisions of 35 U.S.C. Section 112, paragraph 6. Moreover, even if the provisions of 35 U.S.C. Section 112, paragraph 6, are invoked to define the inventions, it is intended that the inventions not be limited only to the specific structure, material or acts that are described in the preferred embodiments, but in addition, include any and all structures, materials or acts that perform the claimed function, along with any and all known or later-developed equivalent structures, materials or acts for performing the claimed function.
For example, there is disclosed a graphics processor that produces the video signals, processed from the analog camera signals, which are input to the display device. The specific form of the graphics processor is not important to the invention. Processing of the video signals can be implemented using single or multiple microprocessors, digital signal processors, or special purpose graphics processors. Thus, it is not the applicant""s intention to limit his invention to any particular form of graphics processor.
Further examples exist throughout the disclosure, and it is not the applicant""s intention to exclude from the scope of his invention the use of structures, materials, or acts that are not expressly identified in the specification, but nonetheless are capable of performing a claimed function.